Answer:
A quarter of the sample.
Explanation:
Let the quantity at the beginning be T. If the element has a half-life of 1,000 years, it means that after 1000 years, T/2 (which represents half the initial quantity available) would have decayed, remaining T/2.
After another 1000 years (making 2000 years), T/4 (which represents have of the quantity left after the first 1000 years) would have decayed, remaining T/4.
This means that only a quarter of T would be left after 2000 years.
Answer:
Genotype is what you can’t see physically and phenotype is the physical characteristics of that organism.
Explanation:Genotype is known as the genetic makeup of an organism. Think the genes behind what your seeing.
Phenotype is the physical characteristics of an organism. For example:freckles,eye color, open or closed earlops..... things of that nature.
Answer:
25%
Explanation:
According to this question, a seek stored seeds of a rare and endangered plant. In order to ensure that the seeds remain fresh, 120 seeds are selected to be grown. However, out of these 120 seeds, only 90 germinated. This means that only 90 of 120 seeds are fertile.
This further means that (120-90) = 30 seeds are infertile and hence, could not germinate. In percentage, this can be represented as:
30/120 × 100
= 1/4 × 100
= 100/4
= 25% of the selected seeds are infertile.
Answer:
A surface wave is a wave that moves along the interface of two different materials, like air and water.
Explanation:
Answer: B. Water breaks down into oxygen molecules for respiration.
Water is the required for photosynthesis, a process by which plants (terrestrial and aquatic) makes their food by utilizing water as a reactant to produce oxygen and glucose as product. The glucose act as a source of energy for conducting various metabolic processes in plants but oxygen is released in the air.

This oxygen is necessary for terrestrial and aquatic animals for respiration. Therefore, water breaks down into oxygen by the process of photosynthesis, hence water plays important role in respiration in living beings.